N.Y.C. Marathon starts under tight security

NEW YORK (CNN) --Thousands of runners raced across the Verrazano Narrows Bridge Sunday morning as the New York City Marathon got under way amid tightened security.

New York Harbor was closed before the race began to safeguard the bridge linking Staten Island to Brooklyn. An estimated 30,000 runners, preceded by wheelchair racers, were to cross the suspension bridge in the first two miles.

Armed Coast Guard officers patrolled the harbor, and all boats were barred from coming within 500 yards of the bridge until 20 minutes after the last runner crossed it, said marathon spokesman Richard Finn.

As a precaution, runners were warned not to accept water or anything else from bystanders.

"Anything you bring with you will have to be in a clear plastic bag, and be expected to be searched as you board the buses," Allen Steinfeld, chief executive officer of the New York Road Runners Club told runners.

The 26.2-mile race -- which also weaves through the boroughs of Brooklyn, Queens, the Bronx and Manhattan -- is dedicated to victims of the September 11 World Trade Center attacks and the rescuers.

The club, which hopes to raise $1 million for victims' families, said the course of the race was changed to avoid the Trade Center site by eliminating the Mile 23 hill leading into Central Park in Manhattan.